美国Ohio State University Herman Shen教授系列讲座（二）
讲座名称：
美国Ohio State University Herman Shen教授系列讲座（二）
讲座时间：
2015-07-07
讲座人：
Herman Shen
形式：
校区：
兴庆校区
实践学分：
讲座内容：
美国Ohio State University 理论与应用力学实验室主任Herman Shen教授讲座二：THE OHIO STATE UNIVERSITY COLLEGE OF ENGINEERING OVERVIEW & ASSESSMENT OF FRACTURE TOUGHNESS AND FATIGUE CRACK GROWTH THRESHOLD OF A WELDED JOINT CONSTITUENTOF A STEAM TURBINE ROTOR
应能源与动力工程学院热动力工程系主任袁奇教授的邀请，美国The Ohio State University，研究生办公室主任、理论与应用力学实验室主任Herman Shen教授于7月4日至7月11日来我校进行学术访问，并在期间举行系列学术讲座，欢迎各位老师和同学届时参加讲座并讨论交流。
讲座二: THE OHIO STATE UNIVERSITY COLLEGE OF ENGINEERING OVERVIEW & ASSESSMENT OF FRACTURE TOUGHNESS AND FATIGUE CRACK GROWTH THRESHOLD OF A WELDED JOINT CONSTITUENTOF A STEAM TURBINE ROTOR
讲座时间：2015年7月7日 上午9:00
讲座地点：能源馆220会议室
讲座人：Herman Shen教授
讲座内容：
Established in 1870, The Ohio State University has focused on engineering and the sciences since its beginning. The Department of Mathematics and Engineering was one of the original seven departments, and in 1882, the SchoolofEngineeringwas instituted. Today, we offer 13 undergraduate and 17 graduate engineering programs through our 11 engineering departments, as well as two undergraduate and three graduate degrees from the Knowlton School of Architecture. Ohio State is the largest, most comprehensive public research university in the country, ranked in the top 25 of all public universities overall in both research and education and ranked 7th in public-university research expenditures programs, 12th overall.
Many power station components for example, steam turbine rotors are joined by welding. During operations, these welded joints are exposed to high temperature corrosive environments severely experiencing cyclic or fatigue loadings. The base metal (BM), weld metal (WM) and heat affected zone (HAZ) of a welded joint constituent have different microstructural and mechanical properties and there can also be a presence of thermal residual stresses in these locations. As a result, the welded joints of a steam turbine rotor become the most vulnerable to fracture during operations. After exceeding a threshold value (fracture toughness), crack growth can initiate and continue through the welded joint constituents and finally can lead to a catastrophic failure of the turbine rotor. In order to ensure safety and reliability of steam turbine welded rotors, a thorough investigation focusing on evaluation of crack initiation, growth, and resistance parameters of BM, WM and HAZ of a steam turbine rotor welded joint constituent will be presented. Fatigue crack growth rate (FCGR) tests were performed first to determine the fatigue crack growth properties of welded joints of a steam turbine rotor by constructing fatigue crack growth curves. A single edge notch bend (SENB) specimen was loaded in a three-point bend fixture at room temperature. The fatigue crack growth parameters (C and m) were assessed for BM, HAZ and WM. In addition, the values of fatigue threshold of BM, WM and HAZ were obtained and compared in order to determine which location is more susceptible to crack initiation during services.
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